Throughout, we follow the same standard nomenclature for the naming of the lobes and hotspots of Cygnus A (e. g. [1]}) and
define the spectral index as \(S_{\nu } \propto \nu ^{\alpha }\) . At the redshift of Cygnus A (\(z =0.0561\) ), 1 arcsec corresponds to a projected distance of 1.089 kpc for a \(\Omega _{\rm M} = 0.3\) , \(\Omega _{\Lambda } = 0.7\)  flat-cosmology with \(H_{0} = 70\)  km s\(^{-1}\)  Mpc\(^{-1}\) .
